Investors in Gulf Keystone Petroleum (LSE: GKP) were given a boost today, with the company reporting that it has received a further gross payment of $15m for Shaikan crude oil export sales. This satisfies the company’s invoice for December and is the fourth consecutive payment received for oil export sales from the Kurdistan Regional Government (KRG).

Following the payment, Gulf Keystone’s cash position is $58.4m. While it’s highly encouraging to see further payments being made, the company is still owed millions of dollars in previously unpaid invoices. While these are being considered for payment in 2016, there’s no certainty that they’ll be satisfied in full. Furthermore, with the political outlook for the region being highly uncertain, there’s no guarantee that continued payments will be received for January onwards.

Of course, it could be argued that this risk is already priced-in since Gulf Keystone trades on a price-to-book (P/B) ratio of only 0.9. However, with the risk of a falling oil price added to the mix, the risk/reward ratio for the company appears to remain relatively unfavourable – even though it has a high quality asset base that has huge potential.

Growth potential?

Also trading on a low valuation is support services company Petrofac (LSE: PFC). Its shares have lost 51% of their value over the last five years. And while they’ve shown strength of late, the company’s improved earnings outlook doesn’t yet appear to have been priced-in by the market.

Evidence of this can be seen in Petrofac’s forward price-to-earnings (P/E) ratio, which currently stands at 8.3 owing to a forecast rise in net profit of 174% in the current year. Additionally, Petrofac currently yields 5.2% from a dividend that’s due to be covered 2.3 times by profit in the current year. As such, it’s relatively secure and even has headroom to grow over the medium term.

Clearly, the energy industry is experiencing a highly challenging period. But while Petrofac comes with a relatively high degree of risk, its valuation and income prospects appear to tip the balance in the investor’s favour. This makes it a strong, albeit volatile, buy at the present time.

Long-term confidence

Meanwhile, copper miner Antofagasta (LSE: ANTO) is also due to deliver improved financial performance during the course of the year. Its bottom line is forecast to rise by 55% in 2016. And as with Petrofac, it trades on a rather lowly valuation, with Antofagasta having a price-to-earnings growth (PEG) ratio of just 0.5.

With Antofagasta having made asset disposals in recent years, its financial standing appears to be relatively healthy. Certainly, its future performance is highly dependent on the price of copper and while it could come under pressure in the short run, Antofagasta’s shares appear to factor-in this risk.

Furthermore, with the company due to lift dividends by 53% in the current year, investor sentiment could begin to improve as rising shareholder payouts signal the confidence of Antofagasta’s management in its long-term financial future.

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Peter Stephens owns shares of Petrofac. The Motley Fool UK owns shares of and has recommended Petrofac. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.